Linewidth loss measurement
CA 1298414 C · Owner: British Telecommunications Public Limited Company · Inventors: Blackburn, David W.J.; Gill, Michael D.; Saunders, Malcolm P.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A method of measuring linewidth loss during the formation of microelectronic circuitry including the, formation of a test pattern constituted by a series of spaced bars on a photographic mask which is to be used to form a predetermined pattern on a substrate material. Either of the bars or the gaps between the bars have the same predetermined width. In the former case the gaps and in the latter case the bars, have widths which differ incremently stepwise from one to the next. The series of bars are such that the ratio of the widths of one adjacent bar/gap pair is unity. The resultant pattern which is formed on the substrate as a complement of the test pattern is then inspected and, the …
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Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Granted March 31, 1992. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended March 31, 2009.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.